Energy, emissions, and economics of institutional solar PV cooking: evidence from an experimental study

Abstract

• Institutional solar steam cooking is more energy efficient as it requires less water to cook. • Solar steam cookers reduce energy use by 90 % compared to biomass cookstoves. • Heat loss is minimised in the solar steam cooker, improving overall energy efficiency. • Solar steam cooking saves costs, with a payback period of 4.8–6.8 years. • Capital subsidies (40 %–80 %) can reduce the payback period to as low as 0.5–1 year. For many countries in the global south, especially in Africa, cooking is done using biomass fuels, with severe indoor air pollution, negative health hazards, and environmental pollution. Therefore, transitioning to cleaner cooking fuels using renewable energy is critical to decarbonize the cooking sector. In this study, analyses were conducted on the energy, emissions, and economics of an innovative solar PV electric steam cooker (SESC), and the results were compared with a traditional biomass cookstove system (BCS) for institutional cooking. The SESC has sand as thermal energy storage incorporated into the design. Experiments were conducted on the SESC and the BCS to cook a common staple food (kenkey) in four senior high schools in Ghana. The experimental results show that the SESC reduces energy consumption by approximately 90 %, achieves an average thermal efficiency of 37.4 % (compared to 14.8 %-14.9 % for BCS), and eliminates direct emissions. The energy savings of the SESC are due to minimal heat losses because of its brick insulation, and the fact that the heated sand is able to hold heat and sustain cooking even when the solar PV energy source is turned OFF. In addition, the lifecycle cost analysis indicates that the SESC has a lower levelized cost of cooking a meal (4.8–6.3 USD/meal) compared to the BCS (8.4–10.5 USD/meal). The payback period for the SESC ranges between 4.8 and 6.8 years, making it financially viable for large-scale institutional cooking. The findings highlight the potential of solar steam cooking as a viable institutional clean cooking solution, with implications for policy interventions and subsidy programmes to promote adoption in large-scale food preparation settings.